How to Measure Distances Out There

Daniel Altschuler: How do you measure distances out there? He says it's like building a ladder of stepping stools. There are other ways things can get dim, such as dust cloud between us and one of these galaxies that'll make it look dimmer which would make it look further away. We want to know if the universe is getting bigger or smaller because we care about our great-great grandkids he says.